Fusible link device for hold open door closers



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Sept. 27, 1960 E. L. SCHLAGE 2,954,106

FUSIBLE LINK DEVICE FOR HOLD OPEN DOOR CLOSERS Filed Aug. 24. 1954 3 Sheets-Sheet 1 A 32 FIE| E [6 15 MQ M' Arrow/[rs INVENTOR. ERNEST L. SC/ILAGE Sept. 27, 1960 E. L. SCHLAGE FUSIBLE LINK DEVICE FOR HOLD OPEN DOOR CLOSERS Filed Aug. 24. 1954 3 Sheets-Sheet 2 INVENTOR. ERA/EST LSCHLAGE ,4, M sFW ATTOPA/EKS p 1960 E. L. SCHLAGE 2,954,106

FUSIBLE LINK DEVICE FOR HOLD OPEN DOOR CLOSERS Filed Aug. 24. 1954 3 Sheets-Sheet 3 1 g I I FIE-1 I] JNVENTOR. ERA/EST L. SCHLAGE ,47' TOP/V1945 United States Patent C FUSIBLE LINK DEVICE FOR HOLD OPEN DOOR CLOSERS Ernest L. Schlage, Burliugame, Calif assiguor to Schlage Lock. Company, a corporation Filed Aug. 24, 1954, Ser. No. 451,852

4 Claims. (Cl. 189-45):

' This invention relates-to door closer attachmentsand more particularly to afusible link release device for use with a door closer having engageable hold opensurfaces;

The use of frictionally engageable surfaces in'holdopen mechanisms for door" closers is Well known in the art as an expedient for holding doors in the open position against the action of a closer; a manual force hein'grequired to disengage the surfacesto allow-the closer to operate; It is, however, both desirable' and necessary; especially in public buildings and the like; toprovide means for automatically disengaging; such surfaces or otherwise releasing such hold open mechanism in caseof a fire to automatically close the: door. Closed doors are a great preventative to the spread of fire and' it is therefore important" that provision be made to' activate door closers which maybe-held open and unattended.

' It-istherefore aprim-ary object of this invention to provide a device for rendering' a door closer hold open mechanism inoperative in case of'fi're;

It is a further-object'ofthis invention to" provide means responsive to heat above a predetermined temperaturefor releasing a hold open door closer.

Still another object of this invention is the provision of a heat releasable device for use with a door closer:

It is a further object of this invention to provide a safe; positive acting fusible link hold opendevice fora d'oorcloser.

A still further object of thisinventiOnis the provisionof a fusible link device for a door closer having engageable hold open surfaces, which device also acts as an overload safety for such door closer;

It is yet another object of this inventionto provide a fusible link-device for a hold open door' closer from which device 110- parts are dropped when such' devicereleases.

Other objects and advantages will become apparent from. the following description takenin' connection with the accompanying drawings in which:

Fig. 1 is a perspective view of the device of this invention in place on the elbow of a door closer mounted between ado'or and its frame;

Fig; 2 is a greatly enlarged fragmentary cross-sectional view taken along line 2l-2 of Fig. 1;

Fig. 3 is an exploded perspective-view of the hold open mechanism with which the device of this invention is adapted to-be associated;

Fig. 4- is a side elevational view of the assembled device of this invention;

Fig. 5 is a top plan view of" the device ofFig. 4 in the operative or unreleased position;

Fig. 5A is a partial topplan view similar to Fig; 5' but showing a modification ofthedevice thereof;

Fig. 5B is a cross-sectional viewtaken along line 5B--5B of Fig. 5A;

Fig. 6'i's a to'pplan view similar to Fig; S but showing the device inthe released position;

Fig. 7 is asectional view'of'a wall, looking down on a: door, and showing the device of this-inventionin place" Fig. 10 is atop-plan view-similar toFig. 5 but showing a further-modification ofthe device thereof with the re-' leased position being shown in-dot-dash lines;

Fig. 11 is a top plan view similar to Fig; 5' but showinganother modification of the device thereof with the released position being shown in dot-dash lines; and,

Fig; 12 is a top plan view similartoFig. 5 but showing a still further modification ofthedevice thereof with thereleased position being shown in dot-dash lines.

In detail, referring to- Fig; 1, the device of this invention' isfor use with a conventional door closer I which is shown mountedon a door 2 hingedly attached to frame- 3 in thecustomary manner. Connecting door closer 1- to frame 3 is'a liukage'comprising'a pair of arms 4, 5' being pivotally connected at an elbow generally designated 6. Arm 4 may berigid throughout its length and is pro-- vided with bosses 8, 9 for'securing it to closer 1 and arm: 5; respectively. Arm Sisshown as being threadedly' ad'- justable and is providedwithboss 10' (Fig. 3), for connection to arm 4 at' elbow 6; and is pivotally connected Boss 9 on arm 4 is seen (Fig. 3) to be formed with a rectangular hole 12therethrough to receive the rectangular shank 13 of pivot bolt 14; and the underside of boss 9- may be recessed as" at 15 (Fig. 2) to receive the head 16' of such bolt. Boss 10 of arm 5 is provided with a large, internally threaded bore 18 which receives externally threaded cylindrical block 19- therein. Block 19 is also formed with rectangular hole 20 for receiving shank 13 of" bolt 14' when the parts are assembled as shown in Fig. 2.

superposed on top of boss 10 is Washer 21 having its' top face centrally recessed as at 22 and beingformed' with rectangular hole 23' (Fig. 3'); which likewise receives shank 13 therethrough. The end 24 of bolt 14* opposite head'16, which protrudes above washer 21 as shown in Fig. 2, is threaded to receive nut 25; Interposed between Washer 21 and nut 25 are the marginal portions 28, 29 of a pair of elongated elements or clamp levers 30; 31' respectively, fora purpose to be described; Boss 9; block 19, washer'21, and marginal portions 28; 29- are.

therefore rigidly secured together in stacked relationshipby bolt 14 and nut 25 and portions 28; 29 act asa spacing Washer insuch stack.

In the operation of the hold open mechanism shown in Figs; 2 and' 3, excluding elements 30', 31 and assuming nut 25 to be in contact with Washer 21, it will be noted' that relative angular movement between arms 4 and 5'- causes bolt 14, block 19, washer 21', and-'nut 25 to rotatewith arm 4 because of rectangular hole 12, rectangular shank 13, and rectangular holes 20; 23. Therefore, boss 10- of arm 5- is caused to travel on thethreads of block 19. The hand of thethreads is suchthat as d'oor'2' is opened outwardly of frame 3; boss 10 travels upwardly toward washer 21- andnut 25' and at apredetermined angularity between arms 4 and 5 the upper face 17 ofboss 10 frictionally engages thelower face'of washer 21' there= by preventing further movement between arms 4, 5. When suflicient force has been applied to door 2 to adequately frictionally engage face 17 with washer 21, the power of door closer 1 is not suflicient to overcome such frictional engage-ment. The door will then be held in the open position until such time as a manual force is applied to the door in a reverse direction to break such frictional engagement and allow closer 1 to close door 2 in the normal manner.

Returning to previously described clamp levers 30, 31, which are elements of the fusible link release device of this invention generally designated 32 (Figs. 4, 5), marginal portions 28, 29 thereof are seen to be circularly recessed and formed with bevelled edges 33, 34 centrally of levers 30, 31. The ends 35, 36 on one side of marginal portions 28, 29 of clamp levers 30, 31, respectively, are

swingably or pivotally connected by cross link 37 and rivets 38 whereas the other ends 39, 40 extend further from marginal portions 28, 29 and are free.

Clamp lever 30 has rotatable cam follower 41 mounted thereon in the same relative position but onthe opposite side of marginal portion 28 from rivet 38. Substantially opposite cam follower 41, but on clamp lever 31, is a pivot pin 42 on which is pivotally mounted one leg 44 of the substantially U-shaped main portion of lock lever 43. The other leg 45 of such lock lever extends around and is in contact with the opposite side of cam follower 41 from pivot pin 42. It is obvious that any projection engageable by leg 45 would serve the purpose of cam follower 41, but said cam follower has the advantage-of low friction operation, for a purpose to be described.

Extending from the main U-shaped portion of lock lever 43 is extension 46, and it is seen that end 39 of clamp lever 30 is longer than end 40 of clamp lever 31 and is formed to a generally opposite contour to that of extension 46. Such end 39 and extension 46 are each provided with an outwardly directed notch 47 adapted to re ceive the edge of an aperture in a fusible or heat releasable link 48 when the tips 49 of end 39 and extension 46 extend through such aperture. 7

- In the modification shown in Figs. 5A and 5B, end 39 and extension 46 are each apertured to receive screws 59 which serve to secure fiber bushings 53 and fiber washers 54 to said end and said extension. The shank of each bushing 53 extends through an aperture in one end of fusible link 48 which thereby holds said end and said extension in the spaced relationship shown. Since each end of link 48 is positioned between the enlarged head of bushing 53 and washer 54 it cannot be unintentionally removed from the assembly and is insulated (by fiber wash-' ers 54) from end 39 and extension 46.

Torsion spring 50 is further provided around pivot pin 42 and has its leaves in contact with the inwardly directed edges of end 39 and extension 46 tending to spread such end and such extension apart.

Referring to Fig. 2 it will be seen that the underside of nut 25 is bevelled to form a mating surface with bevelled edges 33, 34 of clamp levers 30, 31 when marginal portions 28, 29 thereof are interposed or wedged between such nut and Washer 21. Such marginal portions act as a spacer in the rigid stack of parts shown in Fig. 2.

Hence, when surface 17 of boss 10 is forced into engagement with the underside of washer 21, as previously described, such force is transmitted, via washer 21 and nut 25, to levers 30, 31 and tends to spread them apart because of said bevelled edges. Such force is resisted by cross link 37 and by the U-shaped portion of lock lever 43 (Fig. 5).

If a fire should occur when the door is in the hold open position shown in Fig. 1, upon a predetermined temperature being attained link 48 melts apart enabling spring 50 to force extension 46 away from end 39 thereby rotating leg 45 of lock lever 43 out of engagement with cam follower 41. Such action is shown as having occurred in Fig. 6 which illustrates the increased gap between edges 33, 34 caused by the force applied thereto by the hold open mechanism of Fig. 2. The occurrence of such gap removes edges 33, 34 from their wedging position and allows washer 21 to move upwardly and out of frictional engagement with surface 17 of boss 10, thereby releasing the hold open mechanism and allowing closer 1 to close door 2 in the normal manner.

Legs 44, 45 of lock lever 43 are further provided with downwardly turned dogs 51, 52 respectively, for the purpose of preventing movement of such lock lever beyond the position shown in Fig. 6. Since the fusible link device 32 is mounted in a generally horizontal position (Fig. 1), when fusible link 48 parts it will be noted that no portion of such device is dropped but that all portions thereof remain in place on elbow 6 with each half of link 48 hanging from tips 49 of end 39' and extension 46 or from bushings 53.

Release device 32 also acts as an overload safety for the hold open mechanism shown in Figs. 2, 3 since any undue force applied between boss 10 and washer 21 will be transmitted to and taken up by device 32 rather than deforming any of the parts of the hold open mechanism.

Figs. 7, 8 illustrate the variability of application of device 32 by showing such device mounted adjacent bracket 55 rather than at elbow 6 as in Fig. l. The installation of Fig. 7 includes closer 56, mounted on door 2, and pivotally connected arms 57, 58 the latter of which is pivotally connected to bracket 55, mounted on frame 3, by a hold open mechanism similar to that shown in Fig. 2. The operation of the hold open mechanism and device 32 as shown in Figs. 7, 8 is identical with that described in.

be in a most sensitive position and will immediately prevent the spread of such fire by releasing the hold open mechanism upon the predetermined temperature having It is obvious that the fusible link device been attained. can be reversed, end-for-end, from the position shown in Figs. 7, 8, if desired.

Fig. 9 shows -a modification of device 32, generally designated 60, the operation of which is substantially the same as that described for device 32. Release device 60 comprises a pair of clamp levers 61, 62 having bevelled edges 63, 64 similar to edges 33, 34 of device 32 and having the ends 65, 66 thereof flexibly connected by cross link 67 and rivets 68. On opposite ends 69, 70 of levers 61, 62 respectively, cam follower 71 and pivot pin 72 are similarly placed. A generally U-shaped lock lever 73 has one of its legs 74 pivoted about pin 72 whereas the opposite leg 75 is in like engagement with the opposite side of cam follower 71 from pivot pin 72. Leg 75 and the central portion of lever 61 are each provided with a pin 76 for connecting fusible link 78 therebetween to hold leg 75 in contact with cam follower 71.

On the opposite side from pin 76, lock lever 73 ising leg 75 from cam follower 71 and allowing the device to spring to the open position as shown by dot-dash line in Fig. 9.

It is important to note that in both devices 32 and 60 the greater portion of the force transmitted from the hold open mechanism to clamp levers 30, 31 and 61,62

tending to force said clamp levers apart is resisted by.

to resisting the relatively light tension alforded bysprings. 50, 80 respectively. Furthermore, the relative placement of cam followers 41, 71, pivot pins 42, 72, and legs 45, 75, is such that once fusible links 48, 78' aremelted apartsprings 50; 80- need only exertarelatively slight'force-to open'the respective devices 32, 60 'by rollingllegs 45, 75 around cam followers'41, 71.

Figs. l:and ll illustrate similar modificationsof devices-32, 60, each having a pair of clamp levers 81', 82 with similar bevelled edges 83; 84. Adjacent ends 85, 86 such levers-are similarly joined by crosslink 87 and: rivets 88 and-the other extended end 89 of lever 81 is formed with notch 97 for receiving fusible link 98; Pivot-ally connected to the other end 90 of lever 82, as by pivot pin- 92, is cam lever 93 of the device of Fig. 10. Such cam lever is provided with an irregularly shaped hole 94 providing a cam surface or edge 95 for cam follower 91, rotatablly secured to clampalever 81' opposite pivot pin 92, Extension. 96 of. cam lever 93 is also provided with a notch 97 for receiving fusible link 98 was to 'holdthe device in the clamped position. The

device of Fig. ll is similarly formed, with the exception of the modified shape of cam lever 103, irregular hole 104, and cam surface or edge 105; extension 106 is provided on cam lever 103 for a similar purpose.

It will be seen that when the devices of Figs. 10, 11 are in the clamped position cam followers 91 bear on one edge 95, 105 of holes 94, 104 near one corner thereof. Such edges act as cams and are so inclined to the longitudinal axis of the devices as to carry the major force, resisting the tendency of clamp levers 81, 82 to spread, between cam follower 91 and pivot pin 92. Only a minor component of the spreading force is transmitted to fusible link 98 by applying a turning moment to cam levers 93, 103.

In this manner fusible link 98 resists only a small force and yet when such link parts under heat, clamp levers 81, 82 are forced to spread by the action of cam levers 93, 103 rotating about pivot pins 92 to the open position shown in dot-dash line in Figs. l0, 11. It will be noted that no spring is necessary to unlock the devices of Figs. 10, 11 because of the inclined cam edges 95, 105.

The modification of Fig. 12 is similar to that of Fig. 11, in that cam lever 113 having irregularly shaped hole 114 is provided pivotally connected to one leg 110 of a generally U-shaped clamp lever 100 by pivot pin 112. The other leg 109 of clamp lever 100 is extended beyond leg 110 for the purpose of receiving fusible link 108, and is provided intermediate its ends with cam follower 111 in engagement with cam edge 115 of hole 114. The cross portion 107 of clamp lever 100 is reduced in cross setional area to provide a flexible connection between legs 109, 110 so that the same may be spread apart upon release of fusible link 108 as previously described. Legs 109, 110 of clam-p lever 100 are further provided with similar bevelled edges 101, 102 adjacent cross portion 107 for wedging between washer 21 and nut 25 of the hold open mechanism. To insure the spreading of clamp lever 100 upon release of fusible link 108 a helical coil compression spring 117 is provided between leg 109 and extension 116 of clamp lever 113. The open position of the device of Fig. 12 is shown in dot-dash line.

It will be noted that the devices of Figs. l0-12 provide a somewhat more compact unit than those of Figs. and 9 and that all the devices described are effectively fool proof in operation.

Although the invention has been described and illustrated in detail such should not be taken as restrictive thereof since it is obvious that other modifications could be made therein without departing from the spirit and scope of the invention.

- 1.. In; combination with a: door." closer having hold: open means including frictionally" engageable. surfaces for preventing .roperativemovement of saiddoor closer when said. surfacesare jammedf together, a fusible link. release d'e vice comprising: a pair of. clamp leversconnected atone end thereof iandvhaving central, opposed, marginalv poritions: spaced apart a predetermined distance. and in. imming relation with said surfaces. for." jamming the. same I0 together, a. cam. follower mounted: on one of said.

so located: that said cam follower is within the. big-ht thereof, and having an' integral edge in. engagement with the. sideof said cam follower opposite said other clamp lever for holding said marginal portions spaced at said distance against the force of said jammed surfaces tending to separate said clamp levers, said lock lever being rotatable about? said point; for moving said edge out of engagement with. said cam follower; saidedge diverging slightly inia direction toward saidmarginal portions from a line. at. right angles to the linebetween said cam follower and. said point whereby a relatively small portion of the force tending to separate said clamp levers is applied to tend to so rotate said lock lever, extensions on the other end of said one clamp lever and said lock lever, and means including a fusible link interconnecting said extensions for preventing rotation of said lock lever whereby, when said link parts under the influence of heat, said lock lever rotates permitting said clamp levers to spread apart and said marginal portions to be forced out of jamming relationship with said frictionally engageable surfaces, thereby permitting the operative movement of said door closer.

.2. In combination with a hold open door closer having a pair of frictionally engageable surfaces for preventing operative movement of said door closer, a fusible link release device comprising: a pair of clam-p levers pivotally connected at one end thereof and having central, opposed, bevelled-edge, marginal portions spaced apart a predetermined distance and wedging said surfaces together, a cam follower mounted on one of said clamp levers spaced from said one end by said marginal portion, a lock lever connected to the other of said clamp levers at a point corresponding to said cam follower and having an edge in engagement with the side of said cam follower opposite said other clamp lever for holding said marginal portions spaced at said distance, said lock lever being rotatable about said point for moving said edge out of engagement with said cam follower, extensions on the upper end of said one clamp lever and said lock lever, an insulating bushing on each said extension, and an apertured, fusible link, said bushings extending through the apertures in said link to connect said extensions for preventing rotation of said lock lever whereby, when said link parts under the influence of heat, said lock lever rotates permitting said clamp levers to spread apart and said marginal portions to be forced out of wedging relationship with said frictionally engageable surfaces, thereby permitting the operative movement of said door closer.

3. In combination with a hold open door closer having a pair of frictionally engageable surfaces for preventing operative movement of said door closer, a fusible link release device comprising: a pair of clamp levers pivotally connected at one end thereof and having central, opposed, bevelled-edged, marginal portions spaced apart a predetermined distance and wedging said surfaces together, a cam follower mounted on one of said clamp levers spaced from said one end by said marginal portion, a lock lever connected to the other of said clamp levers at a point corresponding to said cam follower and having an edge in engagement with the side of said cam follower opposite said other clamp lever for holding said marginal portions spaced at said distance, said lock lever being rotatable about said point for moving said edge out of engagement with said cam follower, a spring acting between said lock lever and one of said clamp levers tending to so rotate said lock lever, stop members on said lock lever and engageable by said clamp levers for preventing rotation of said lock lever beyond that necessary to free said edge from said earn follower, extensions on the other end of said one clamp lever and said lock lever, a fusible link interconnecting said extensions for preventing rotation of said lock lever whereby, when said link pants under the influence of heat, said lock lever rotates permitting said clamp levers to spread apart and said marginal portions to be forced out of wedging relationship with said frictionally engageable surfaces, thereby permitting the operative movement of said door closer.

4. In combination with B, hold open door closer having a pair of frictionally engageable surfaces for preventing operative movement of said door closer, a fusible link release device comprising: a pair of clamp levers con nected at one end thereof and having central, opposed, marginal portions spaced apart a predetermined distance and jamming said surfaces together, a cam follower mounted on one of said clamp levers spaced from said one end by said marginal portion, a lock lever connected to the other of said clamp levers at a point corresponding to said 0am follower and having an edge in engagement with the side of said cam follower opposite said other clamp lever for holding said marginal portions spaced at said distance, said lock lever being rotatable about said point for moving said edge out of engagement with said ea-m follower, a spring acting between said lock lever and one of said clamp levers tending to so rotate said lock lever, extensions on the other end of said one clamp lever and said lock lever, and means including a fusible link insulated from but interconnecting said extensions for preventing rotation of said lock lever whereby, when said link parts under the influence of heat, said lock lever rot-ates permitting said clamp levers to spread apart and said marginal portions to be forced out of jamming relationship with said frictionally engageable surfaces, thereby permitting the operative movement of said door closer.

References Cited in the file of this patent UNITED STATES PATENTS 

